Safety winch



y 27, 1954 J. M. BENSON 2,684,833 SAFETY'WINCH Filed Feb. 18, 1952 2Sheets-Sheet 1 III II III INVENTOR JsseMfienso n mg-4M ATTORNEYS J. M.BENSON SAFETY WINCH July 27, 1954 2 Sheets-Sheet 2 Filed Feb. 18, 1952INVENTOR 8 5 s 6 M59 ATTORNEYS Patented July 27, 1954 UNITED STATESPATENT OFFICE SAFETY WINCH Jesse M. Benson, Concord, Tenn. ApplicationFebruary 18, 1952, Serial N 0. 272,039

4 Claims.

This invention relates to safety winches and winding drums.

In a scaffold winch there drum for the suspension cable with a ratchetmeans to prevent unwinding of the cable. It is an object of thisinvention to provide in a is provided a winding Another object of thisinvention is to provide a safety lock for a winding drum which may bethe winding drum should rotate at an excessive speed, the latter isimmediately locked against further unwinding.

A further object of this invention is to provide a safety lock of thiskind which is simple in con struction and positive in action.

With the above and other objects in view, my

invention.

Figure 2 is a fragmentary side elevation of the device.

Figure 3 is a fragmentary vertical section through the device.

Figure 4 is a fragmentary sectional on the line 4-4 of Figure 3.

Figure 5 is a sectional view taken on the line 55 of Figure 3.

Figure 6 is a sectional view taken on the line 6-6 of Figure 3.

Referring to the drawings, the numeral I0 designates generally a framestructure which is formed of parallel side members II and I2 connectedtogether at their upper ends by a connecting bar I3. The lower ends ofthe side bars II and I2 are secured together by means of a hangersupport I4, which is fixed between the side bars II and I2 by means ofbolts I5. A platform hanger l6 of conventional construction is suspendedfrom the support I4.

A cable winding drum generally designated as view taken I! is rotatablydisposed in the frame In and includes a relatively large spur gear I8,which is fixed to a tubular sleeve I9. A side wall 20 is secured to thesleeve I9 oppositely from the gear I 8. A stationary shaft 2| havingreduced threaded opposite ends 22 is disposed between the frame membersII and I2, and nuts 23 are threaded on the ends 22 so as to hold theframe bars II and I2 in spaced parallel relation and also hold the shaft2| against rotation.

A pawl 24 is rockably carried by the side frame bar II and engages thespur gear I8, which also constitutes a ratchet. The pawl 24 is providedwith an upwardly projecting handle 25 disposed on the forward edge ofthe frame member I3, and the latter limits the rocking movement of thepawl 24 to a released position.

by a pivot member 32, which is fixed to and pro jects inwardly fromframe bar I2. The pawl 3| is a safety pawl, and the latter is normallyheld against locking engagement with ratchet 30 by means of a cam 33,which is carried by a lever or arm 34 integral with pawl 3|.

The cam 33 with lever 34 ment with the ratchet.

The cable 29 is extended upwardly to a suitable supporting structure andis guided above the J frame Ill by means of a pulley 35 carried by apair of ears 36 which are fixed to the upper end of an upright guidesupport 31. The guide support 31 is fixed to the upper frame bar I3.

I do not mean to confine myself to the exact details of constructionherein disclosed, but claim all variations falling within the purview ofthe appended claims.

What is claimed:

1. A winch comprising a frame, a winding drum rotatable in said frame, adriven gear fixed relative to said drum, a drive shaft rotatable in saidframe, a driving gear fixed to said shaft and. meshing with said drivengear, a ratchet fixed to said drive shaft, a pawl rockably carried bysaid frame engaging said ratchet, and a pawl operator fixed to said pawland extending angularly therefrom, said operator comprising an armintegral with said pawl and extending angularly therefrom, and a camcarried by said arm slidingly engaging the teeth of said ratchet, saidoperator normally riding over the teeth of said ratchet and the weightof said operator gravitatingly holding said pawl against lockingengagement with said ratchet, said operator upon reverse rotation ofsaid ratchet at a speed above normal effecting rocking of said pawl tolocking engagement with said ratchet.

2. A winch comprising a frame, a winding drum rotatable in said frame, adriven gear fixed relative to said drum, a drive shaft rotatable in saidframe, a driving gear fixed to said shaft and meshing with said drivengear, a ratchet fixed to said drive shaft, a pawl rockably carried bysaid frame engaging said ratchet, and a pawl operator fixed to said pawland extending angularly therefrom, said operator comprising an armintegral with said pawl and extending angularly therefrom, and a camcarried by said arm slidingly engaging the teeth of said ratchet, saidoperator normally riding over the teeth of said ratchet and the weightof said operator gravitatingly holding said pawl against lockingengagement with said ratchet, said operator upon reverse .ro tation ofsaid ratchet at a speed above normal effecting rocking of said awl tolocking engagement with said ratchet, and a locking pawl carried by saidframe engageable with the teeth of said driven gear.

3. A winch comprising a frame, a winding drum rotatably mounted in saidframe, a driven gear which also constitutes a ratchet, fixed relative tosaid drum, a drive shaft rotatably mounted in said frame, a driving gearfixed to said drive shaft and meshing with said driven gear, a pawlrockably mounted on said frame above said driving gear and having anoperating arm for lifting said pawl, said pawl having a portion normallyengaging the teeth of said driven gear and adapted to ratchet thereover,a ratchet wheel fixed to said drive shaft spacedly from said drivinggear, and a safety pawl pivotally mounted intermediate its ends on saidframe adjacent said ratchet wheel, said safety pawl having a weightedend portion normally lifting said pawl out of engagement with saidratchet wheel and resting on said wheel, said safety pawl having anotherportion to engage said ratchet wheel upon reverse rotation of saidratchet wheel at high speed to effect locking engagement with saidratchet wheel to thereby prevent unwinding of a cable from said drum.

4. In a winch, a frame, a shaft journaled in said frame, a winding drummounted on said shaft for rotation in both winding and unwindingdirections, an operating member having a positive motion-transmittingconnection with said winding drum for imparting winding and unwindingmovements thereto, a ratchet wheel positioned for rotation with saiddrum, a pawl pivoted near its midpoint on said frame and above and inthe plane of said ratchet wheel, said pawl having at one end aratchet-engageable detent and at its other end a weight which normallyrests upon the outer edge of the ratchet wheel and holds the detent outof locking engagement with the ratchet wheel, the pawl being moved aboutits pivot by action of the ratchet wheel on the weighted end of thepawl, upon rotation of the drum in an unwinding direction at a speed inexcess of a predetermined speed, to a position in which the detent is inlocking engagement with the ratchet wheel.

References Cited in the file of this patent UNITED STATES PATENTS

